| 摘要 |
PURPOSE:To facilitate the control of a common rail pressure by providing an overflow solenoid valve in a passage for introducing a pump chamber of a fuel pump to a low pressure side and opening said valve at a proper time during a pressure feeding stroke, at the time of accumulating the pressure of a high pressure fuel in a common rail and injecting said fuel from an injection nozzle. CONSTITUTION:Injectors 2 which are controlled in their opening and closing by the on/off of injection controlling solenoid valves 3 respectively are provided for each cylinder on an engine 1, and connected to a common rail 4 which is commonly used for each cylinder. A fuel high pressure feed pump 7 is connected to the common rail 4 via a feeding piping 5 and a check valve 6. And, in order to control and maintain a common rail pressure at a defined value, a pump discharge quantity control device 10 having an overflow solenoid valve is connected to the pump 7. The overflow solenoid valve in this control device 10 is controlled so as to be previously closed before starting the feeding of fuel under pressure and opened at a defined time during the pressure feeding stroke, by means of an ECU 11 in which the output signals of an engine speed sensor 12 and a load sensor 13 are inputted.
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